
Description of the Tsunami Propagation Model
The model calculations have been performed according to code
GNOM (General hydrostatic/nonhydrostatic Ocean Model). The program generates a
curvilinear grid in a given domain on which the twodimensional or
threedimensional equations transformed to the boundaryfitted coordinates are
integrated by the difference method. At each time step the dynamic equations
are solved in three steps. At the preliminary step the full equations are
integrated implicitly by splitting in the coordinate directions. Horizontal
viscosity operator is expressed in terms of velocity vortex in covariant
presentation. Approximation of an advective operator has an accuracyselector
switch, which allows one to use the schemes of the first, second or third order
of accuracy with adjoined TVD procedure. Then the 2D Poisson equation for
determination of the level is constructed on the basis of the vertically
averaged equations of continuity and correction of velocity. At the next step
the field of velocity is determined from the level. This realization has the
second order of accuracy time and space variables and allows the time step,
which is considerably superior to the usual restriction on the advective mode
in a semiimplicit method.
The model description has been provided by
Alexei Androssov
and
Angelo Rubino.
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